Author: admin

When developing websites, we generally have to reuse the same information or code in many places. For example, we might want the same header, footer or menu across all pages. PHP allows us to use file inclusion instead of writing the same code many times!

File inclusion saves time, organizes our code and allows us to make simple changes. When we make a change to one file, that changes all other files that contain that file.

Types File Inclusion in PHP

You can include the content of a PHP file into another PHP file before the server executes it. There are two PHP functions which can be used to included one PHP file into another PHP file.

• Include() Function
• Require() Function
• Include_once() and Require_once() Function

This is a strong point of PHP which helps in creating functions, headers, footers, or elements that can be reused on multiple pages. This will help developers to make it easy to change the layout of complete website with minimal effort. If there is any change required then instead of changing thousand of files just change included file.

The include() Function

The include() function takes all the text in a specified file and copies it into the file that uses the include function. If there is any problem in loading a file then the include() function generates a warning but the script will continue execution.

Syntax

Below is the syntax of the includefunction −

include'filename.php';

Here, filename.php is the file you want to include. It can be a relative or absolute path.

Example

Assume you want to create a common menu for your website. Then create a file menu.php with the following content.

<a href="http://www.tutorialspoint.com/index.htm">Home</a><a href="http://www.tutorialspoint.com/ebxml">ebXML</a><a href="http://www.tutorialspoint.com/ajax">AJAX</a><a href="http://www.tutorialspoint.com/perl">PERL</a>

Now create as many pages as you like and include this file to create header. For example now your test.php file can have following content.

<?php <b>include("menu.php");</b> ?><p>This is an example to show how to include PHP file!</p>

Output

It will produce the following result −

Advantages of include() Method

Using the include() method in PHP has several advantages −

• Adding a file allows you to reuse the same content on other pages without having to change any code.
• You can add basic website elements like headers, footers, and menus to various pages.
• If the included file has an error, include() will only display a warning message and the script will continue to run.
• If you need to change the included file (for example, to update the header or footer), do so only once, and the changes will be reflected on all pages that use it.

The require() Function

The require() function takes all the text in a specified file and copies it into the file that uses the include function. If there is any problem in loading a file then the require() function generates a fatal error and halt the execution of the script.

So there is no difference in require() and include() except they handle error conditions. It is recommended to use the require() function instead of include(), because scripts should not continue executing if files are missing or misnamed.

Syntax

Below is the syntax of the requirefunction −

require'filename.php';

Here, filename.php is a file you want to require. It can be a relative or absolute path.

Example

You can try using above example with require() function and it will generate same result. But if you will try following two examples where file does not exist then you will get different results.

<?php include("xxmenu.php"); ?><p>This is an example to show how to include wrong PHP file!</p>

Output

This will produce the following result −

This is an example to show how to include wrong PHP file!

Now lets try same example with require() function.

<?php <b>require("xxmenu.php");</b> ?><p>This is an example to show how to include wrong PHP file!</p>

This time file execution halts and nothing is displayed.

NOTE − You may get plain warning messages or fatal error messages or nothing at all. This depends on your PHP Server configuration.

Advantages of require() Method

Using the require() method in PHP has many advantages −

• If the required file is important for the page (for example, a database connection file), require() makes sure the script stops and displays an error if it is not found, preventing the page from loading with limited functionality.
• The function makes sure all necessary files are always available for proper execution. This is useful for files that the website need to work properly.
• Like include(), require() allows you to reuse code across multiple pages.
• With require(), you only need to include the required code once, which reduces duplication.

Difference between include() and require() Methods

The require statement is also used to include a file within PHP code. However, there is one important difference between include and require: if a file is included using the include line but PHP cannot find it, the script will continue to run.

• The include() function shows a warning and continues execution if the file is missing. While the require() method shows a fatal error and stops execution if the file is missing.
• The include() function is basically used for non-critical files for example- header, footer. While require() is used for important files like database connection, configuration.
• The include() method can include a file multiple times unless include_once() is used. And the require() includes a file multiple times unless require_once() is used.
• The include() continues execution even if the file is not present of missing. And require() stops script execution if the file is missing.

The include_once() and require_once() Function

These functions are useful when you have to make sure a file is only included once.

// config.php
<?php
   $database_host = 'localhost';
?>

// settings.php
<?php
   // Includes config.php only once   
   include_once 'config.php'; 

   // It will not include again if called multiple times
   require_once 'config.php'; 
   echo "Database host is: $database_host";
?>

Security Risks of File Inclusion

While file inclusion can make your code easier to work with, it may also create security risks, particularly if users have control over which files are included. This is known as Local File Inclusion (LFI) and can be used by attackers.

Example of a Vulnerable Code

In this scenario, a malicious user may gain access to any file on the server by changing the page query parameter, which could result in data breaches or other vulnerabilities. Here is an example code which you should avoid in your PHP applications −

<?php
   // User can set the page parameter
   $page = $_GET['page']; 

   // This can lead to dangerous inclusions
   include($page); 
?>

Prevent File Inclusion Vulnerabilities

Always check and sanitize any user input before using it in an include statement.

<?php
   $allowed_pages = ['home.php', 'about.php', 'contact.php'];
   if (in_array($page, $allowed_pages)) {
      include($page);
   } else {
      echo "Page not found.";
   }
?>

Instead of including files with user-generated content you can consider using predefined paths. If you don’t need remote file inclusion so you can disable it in your php.ini file.

allow_url_include = Off

Data types in PHP can be of “scalar type” or “compound type”. Integer, float, Boolean and string types are scalar types, whereas array and object types are classified as compound types. Values of more than one types can be stored together in a single variable of a compound type.

In PHP, objects and arrays are the two compound data types.

• An array is an ordered collection of elements of other data types, not necessarily of the same type.
• An object is an instance of either a built-in or a user defined class, consisting of properties and methods.

Arrays in PHP

An array is a data structure that stores one or more data values in a single variable. An array in PHP is an ordered map that associates the values to their keys.

• There are two ways to declare an array in PHP. One is to use the built-in array() function, and the other is to put the array elements inside square brackets.
• An array which is a collection of only values is called an indexed array. Each value is identified by a positional index staring from 0.
• If the array is a collection of key-value pairs, it is called as an associative array. The key component of the pair can be a number or a string, whereas the value part can be of any type.

The array() Function in PHP

The built-in array() function uses the parameters given to it and returns an object of array type. One or more comma-separated parameters are the elements in the array.

array(mixed...$values):array

Each value in the parenthesis may be either a singular value (it may be a number, string, any object or even another array), or a key-value pair. The association between the key and its value is denoted by the “=>” symbol.

Example

Take a look at this following example −

$arr1=array(10,"asd",1.55,true);$arr2=array("one"=>1,"two"=>2,"three"=>3);$arr3=array(array(10,20,30),array("Ten","Twenty","Thirty"),array("physics"=>70,"chemistry"=>80,"maths"=>90));

Using Square Brackets [ ]

Instead of the array() function, the comma-separated array elements may also be put inside the square brackets to declare an array object. In this case too, the elements may be singular values or a string or another array.

$arr1=[10,"asd",1.55,true];$arr2=["one"=>1,"two"=>2,"three"=>3];$arr3=[[10,20,30],["Ten","Twenty","Thirty"],["physics"=>70,"chemistry"=>80,"maths"=>90]];

Accessing Array Elements

To access any element from a given array, you can use the array[key] syntax. For an indexed array, put the index inside the square bracket, as the index itself is anyway the key.

<?php
   $arr1 = [10, 20, 30];
   $arr2 = array("one"=>1, "two"=>2, "three"=>3);

   var_dump($arr1[1]);
   var_dump($arr2["two"]);
?>

It will produce the following output −

int(20)
int(2)

Array Traversal in PHP

You can also use the foreach loop to iterate through an indexed array.

<?php
   $arr1 = [10, 20, 30, 40, 50];
   foreach ($arr1 as $val){
      echo "$val\n";
   } 
?>

It will produce the following output −

10
20
30
40
50

Note that PHP internally treats the indexed array as an associative array, with the index being treated as the key. This fact can be verified by the var_dump() output of the array.

We can unpack each element of the indexed array in the key and value variables with the foreach syntax −

<?php
   $arr1 = [10, 20, 30, 40, 50];
   foreach ($arr1 as $key => $val){
      echo "arr1[$key] = $val" . "\n";
   }
?>

It will produce the following output −

arr1[0] = 10
arr1[1] = 20
arr1[2] = 30
arr1[3] = 40
arr1[4] = 50

The foreach loop is also used for iterating through an associative array, although any other type of loop can also be used with some maneuver.

Let us look at the foreach loop implementation, with each k-v pair unpacked in two variables.

<?php
   $capitals = array(
      "Maharashtra"=>"Mumbai", 
      "Telangana"=>"Hyderabad", 
      "UP"=>"Lucknow", 
      "Tamilnadu"=>"Chennai"
   );

   foreach ($capitals as $k=>$v) {
      echo "Capital of $k is $v" . "\n";
   }
?>

It will produce the following output −

Capital of Maharashtra is Mumbai
Capital of Telangana is Hyderabad
Capital of UP is Lucknow
Capital of Tamilnadu is Chennai

Objects in PHP

In PHP, an object is a compound data type. It is an instance of either a built in or user defined class. Given below is a simple PHP class −

classSayHello{functionhello(){echo"Hello World";}}

To declare an object of a class, we need to use the new operator.

$obj=newSayHello;

We can now call its method −

<?php
   class SayHello {
      function hello() {
         echo "Hello World". PHP_EOL;
      }
   }

   $obj=new SayHello;
   var_dump(gettype($obj));
   $obj->hello();
?>

It will produce the following output −

string(6) "object"
Hello World

The stdClass

PHP provides stdClass as a generic empty class which is useful for adding properties dynamically and casting. An object of stdClass is null to begin with. We can add properties to it dynamically.

<?php
   $obj=new stdClass;
   $obj->name="Deepak";
   $obj->age=21;
   $obj->marks=75;

   print_r($obj);
?>

It will produce the following output −

stdClass Object (
   [name] => Deepak
   [age] => 21
   [marks] => 75
)

Array to Object Conversion in PHP

An array in PHP can be typecast to an object as follows −

<?php
   $arr=array("name"=>"Deepak", "age"=>21, "marks"=>75);
   $obj=(object)$arr;

   print_r($obj);
?>

It will produce the following output −

stdClass Object (
   [name] => Deepak
   [age] => 21
   [marks] => 75
)

Object to Array Conversion in PHP

Conversely, an object can be cast to an array. Take a look at the following example −

<?php
   $obj=new stdClass;
   $obj->name="Deepak";
   $obj->age=21;
   $obj->marks=75;

   $arr=(array)$obj;
   print_r($arr);
?>

It will produce the following output −

Array
(
   [name] => Deepak
   [age] => 21
   [marks] => 75
)

Scalar Type to Object Type Conversion in PHP

A variable of any scalar type can also be converted to an object by type casting. The value of the scalar variable becomes the value of the object’s scalar property.

<?php
   $name="Deepak";
   $age=21;
   $percent=75.50;

   $obj1=(object)$name;
   print_r($obj1);

   $obj2=(object)$age;
   print_r($obj2);

   $obj3=(object)$percent;
   print_r($obj3);
?>

It will produce the following output −

stdClass Object
(
   [scalar] => Deepak
)
stdClass Object
(
   [scalar] => 21
)
stdClass Object
(
   [scalar] => 75.5
)

Heredoc and Nowdoc are PHP methods that allow you to write long strings without using too many quotes or escape characters. They allow you to write multi-line strings in a neat and readable manner.

PHP provides two alternatives for declaring single or double quoted strings in the form of heredoc and newdoc syntax.

Heredoc is useful for including variables, but Nowdoc is useful to get raw text without variable change.

• The single quoted string doesn’t interpret the escape characters and doesn’t expand the variables.
• On the other hand, if you declare a double quoted string that contains a double quote character itself, you need to escape it by the “\” symbol. The heredoc syntax provides a convenient method.

Heredoc Strings in PHP

The heredoc strings in PHP are much like double-quoted strings, without the double-quotes. It means that they don’t need to escape quotes and expand variables.

Heredoc Syntax

$str=<<<IDENTIFIER
place a string here
it can span multiple lines
and include single quote ' and double quotes "
IDENTIFIER;

First, start with the “<<<” operator. After this operator, an identifier is provided, then a newline. The string itself follows, and then the same identifier again to close the quotation. The string can span multiple lines and includes single quotes () or double quotes (“).

The closing identifier may be indented by space or tab, in which case the indentation will be stripped from all lines in the doc string.

Example

The identifier must contain only alphanumeric characters and underscores and start with an underscore or a non-digit character. The closing identifier should not contain any other characters except a semicolon (;). Furthermore, the character before and after the closing identifier must be a newline character only.

Take a look at the following example −

<?php  
   $str1 = <<<STRING
   Hello World
      PHP Tutorial
         by TutorialsPoint
   STRING;

   echo $str1;
?>

It will produce the following output −

Hello World
    PHP Tutorial
        by TutorialsPoint

Example

The closing identifier may or may not contain indentation after the first column in the editor. Indentation, if any, will be stripped off. However, the closing identifier must not be indented further than any lines of the body. Otherwise, a ParseError will be raised. Take a look at the following example and its output −

<?php  
   $str1 = <<<STRING
   Hello World
      PHP Tutorial
   by TutorialsPoint
   STRING;
         
   echo $str1;
?>

It will produce the following output −

PHP Parse error:  Invalid body indentation level 
(expecting an indentation level of at least 16) in hello.php on line 3

Example

The quotes in a heredoc do not need to be escaped, but the PHP escape sequences can still be used. Heredoc syntax also expands the variables.

<?php  
   $lang="PHP";
   echo <<<EOS
   Heredoc strings in $lang expand vriables.
   The escape sequences are also interpreted.
   Here, the hexdecimal ASCII characters produce \x50\x48\x50
   EOS;
?>

It will produce the following output −

Heredoc strings in PHP expand vriables.
The escape sequences are also interpreted.
Here, the hexdecimal ASCII characters produce PHP

Nowdoc Strings in PHP

A nowdoc string in PHP is similar to a heredoc string except that it doesn’t expand the variables, neither does it interpret the escape sequences.

<?php  
   $lang="PHP";

   $str = <<<'IDENTIFIER'
   This is an example of Nowdoc string.
   it can span multiple lines
   and include single quote ' and double quotes "
   IT doesn't expand the value of $lang variable
   IDENTIFIER;

   echo $str;
?>

It will produce the following output −

This is an example of Nowdoc string.
it can span multiple lines
and include single quote ' and double quotes "
IT doesn't expand the value of $lang variable

The nowdoc’s syntax is similar to the heredoc’s syntax except that the identifier which follows the “<<<” operator needs to be enclosed in single quotes. The nowdoc’s identifier also follows the rules for the heredoc identifier.

Heredoc strings are like double-quoted strings without escaping. Nowdoc strings are like single-quoted strings without escaping.

Mathematical operations are important parts of programming. PHP has several built-in math functions that make calculations easy. These functions can be used to round numbers, find maximum and minimum values, work with exponents and logarithms and so on.

In this chapter, we will look at different PHP math functions and mathematical (arithmetic) operators and how they can be used with the help of some examples. If you need to calculate absolute values, round numbers or perform complex mathematical operations, PHP’s math functions make it easy and efficient.

List of Math Functions

Here is the list of functions available in PHP −

Function	Description
abs($num)	Returns the absolute (positive) value of a number.
ceil($num)	Rounds a float number up to the next highest integer.
exp($num)	Returns Euler’s number (e) raised to the power of the given number.
floor($num)	Rounds a float number down to the next lowest integer.
intdiv($x, $y)	Returns the integer quotient of two integers (ignoring remainder).
log10($num)	Returns the base-10 logarithm of a number.
max($values)	Returns the highest value from an array or multiple values.
min($values)	Returns the lowest value from an array or multiple values.
pow($base, $exp)	Returns the result of raising a number to a given power.
round($num, $precision)	Rounds a number to the nearest integer or specified decimal places.
sqrt($num)	Returns the square root of a number.

PHP abs() Function

The abs() function is an in-built function in PHP iterpreter. This function accepts any number as argument and returns a positive value, disregarding its sign. Absolute value of any number is always positive.

abs(mixed$num)

PHP abs() function returns the absolute value of num. If the data type of num is float, its return type will also be float. For integer parameter, the return type is integer.

Example

Take a look at this following example −

<?php
   $num=-9.99;
   echo "negative float number: " . $num . "\n";
   echo "absolute value : " . abs($num) . "\n"; 

   $num=25.55;
   echo "positive float number: " . $num . "\n";
   echo "absolute value : " . abs($num). "\n";

   $num=-45;
   echo "negative integer number: " . $num . "\n";
   echo "absolute value : " . abs($num) . "\n"; 

   $num=25;
   echo "positive integer number: " . $num . "\n";
   echo "absolute value : " . abs($num);
?>

It will produce the following output −

negative float number: -9.99
absolute value : 9.99
positive float number: 25.55
absolute value : 25.55
negative integer number: -45
absolute value : 45
positive integer number: 25
absolute value : 25

PHP ceil() Function

The ceil() function is an in-built function in PHP iterpreter. This function accepts any float number as argument and rounds it up to the next highest integer. This function always returns a float number as the range of float is bigger than that of integer.

ceil(float$num):float

PHP ceil() function returns the smallest integer value that is bigger than or equal to given parameter.

Example 1

The following code rounds 5.78 to its next highest integer which is 6

<?php
   $arg=5.78; 
   $val=ceil($arg);
   echo "ceil(" . $arg .  ") = " . $val;
?>

It will produce the following output −

ceil(5.78) = 6

Example 2

The following example shows how you can find the next highest integer of 15.05.

<?php
   $arg=15.05; 
   $val=ceil($arg);
   echo "ceil(" . $arg .  ") = " . $val;
?>

It will produce the following output −

ceil(15.05) = 16

Example 3

For negative number, it is rounded towards 0.

<?php
   $arg=-3.95; 
   $val=ceil($arg);
   echo "ceil(" . $arg .  ") = " . $val;
?>

It will produce the following output −

ceil(-3.95) = -3

PHP exp() Function

The exp() function calculates exponent of e that is Euler Number. PHP has a predefined constant M_E that represents Euler Number and is equal to 2.7182818284590452354. Hence, exp(x) returns 2.7182818284590452354x

This function always returns a float.

exp(float$arg):float

PHP exp() function returns the Euler Number e raised to given arg. Note that e is the base of natural algorithm. The exp() function is the inverse of natural logarithm.

Example 1

One of the predefined constants in PHP is M_LN2 which stands for loge2 and is equal to 0.69314718055994530942. So, the exp() of this value will return 2.

<?php
   echo "exp(" . M_LN2 . ") = " . exp(M_LN2);
?>

It will produce the following output −

exp(0.69314718055995) = 2

Example 2

M_LN10 is another predefined constant representing loge10. This program calculates exp(M_LN10) and returns 10.

<?php
   echo "exp(" . M_LN10 . ") = " . exp(M_LN10);
?>

It will produce the following output −

exp(2.302585092994) = 10

PHP floor() Function

The floor() function is another in-built function in PHP interpreter. This function accepts any float number as argument and rounds it down to the next lowest integer. This function always returns a float number as the range of float is bigger than that of integer.

floor(float$num):float

PHP floor() function returns the largest integer less than or equal to the given parameter.

Example 1

The following example shows how to round 15.05 to its next highest integer which is 15

<?php
   $arg=15.05; 
   $val=floor($arg);
   echo "floor(" . $arg .  ") = " . $val;
?>

It will produce the following output −

floor(15.05) = 15

Example 2

The following example shows how to find the next lowest integer of 5.78.

<?php
   $arg=5.78; 
   $val=floor($arg);
   echo "floor(" . $arg .  ") = " . $val;
?>

It will produce the following output −

floor(5.78) = 5

Example 3

Negative numbers are rounded away from 0.

<?php
   $arg=-3.95; 
   $val=floor($arg);
   echo "floor(" . $arg .  ") = " . $val;
?>

It will produce the following output −

floor(-3.95) = -4

PHP intdiv() Function

The intdiv() function returns the integer quotient of two integer parameters. If x/y results in “i” as division and “r” as remainder, then −

x = y*i+r

In this case, intdiv(x,y) returns “i”

intdiv(int$x,int$y):int

The “x” parameter forms numerator part of the division expression, while the “y” parameter forms the denominator part of the division expression.

PHP intdiv() function returns the integer quotient of division of “x” by “y”. The return value is positive if both the parameters are positive or both the parameters are negative.

Example 1

The following example shows that if the numerator is less than the denominator, then intdiv() function returns 0.

<?php
   $x=10;
   $y=3; 
   $r=intdiv($x, $y);
   echo "intdiv(" . $x . "," . $y . ") = " . $r . "\n";
   $r=intdiv($y, $x);
   echo "intdiv(" . $y . "," . $x . ") = " . $r;
?>

It will produce the following output −

intdiv(10,3) = 3
intdiv(3,10) = 0

Example 2

In the following example, intdiv() function returns a negative integer because either the numerator or the denominator is negative.

<?php
   $x=10;
   $y=3; 
   $r=intdiv($x, $y);
   echo "intdiv(" . $x . "," . $y . ") = " . $r . "\n";

   $x=10;
   $y=-3; 
   $r=intdiv($x, $y);
   echo "intdiv(" . $x . "," . $y . ") = " . $r . "\n";

   $x=-10;
   $y=3; 
   $r=intdiv($x, $y);
   echo "intdiv(" . $x . "," . $y . ") = " . $r . "\n";

   $x=-10;
   $y=-3; 
   $r=intdiv($x, $y);
   echo "intdiv(" . $x . "," . $y . ") = " . $r ;
?>

It will produce the following output −

intdiv(10,3) = 3
intdiv(10,-3) = -3
intdiv(-10,3) = -3
intdiv(-10,-3) = 3

Example 3

Denominator is 0 in the following example. It results in DivisionByZeroError exception.

<?php
   $x=10;
   $y=0; 
   $r=intdiv($x, $y);
   echo "intdiv(" . $x . "," . $y . ") = " . $r . "\n";
?>

It will produce the following output −

PHP Fatal error:  Uncaught DivisionByZeroError: Division by zero

Example 4

The fractional parts in both the parameters are ignored. PHP intdiv() function is applied only to the integer parts.

<?php
   $x=2.90;
   $y=1.90; 
   $r=intdiv($x, $y);
   echo "intdiv(" . $x . "," . $y . ") = " . $r . "";
?>

It will produce the following output −

intdiv(2.9,1.9) = 2

PHP log10() Function

The log10 () function calculates the base-10 logarithm of a number. Base-10 logarithm is also called common or standard algorithm. The log10(x) function calculates log10x. It is related to natural algorithm by the following equation −

log10x=logex/loge10 ; So that
log10100=loge100/loge10 =2

In PHP, log10 is represented by log10() function

log10(float$arg):float

PHP log10() function returns the base-10 logarithm of arg.

Example 1

The following code calculates the base-10 logarithm of 100

<?php
   $arg=100;
   echo "log10(" . $arg. ")=" . log10($arg) . "";
?>

It will produce the following output −

log10(100)=2

Example 2

The following code calculates the base-10 logarithm of Euler Number M_E. The result is equal to a predefined constant M_LOG10E

<?php
   $arg=M_E;
   echo "log10(" . $arg. ")=" . log10($arg) . "\n";
   echo "predefined constant M_LOG10E=" . M_LOG10E;
?>

It will produce the following output −

log10(2.718281828459)=0.43429448190325
predefined constant M_LOG10E=0.43429448190325

Example 3

The following code calculates log100 and returns -.

<?php
   $arg=0;
   echo "log10(" . $arg. ")=" . log10($arg) . "";
?>

It will produce the following output −

log10(0)=-INF

Example 4

Similarly sqrt(-1) results in NAN. Hence, its log10() also returns NAN.

<?php
   $arg=sqrt(-1);
   echo "log10(" . $arg. ")=" . log10($arg) . "";
?>

It will produce the following output −

log10(NAN)=NAN

PHP max() Function

The max () function returns the highest element in an array, or the highest amongst two or more comma separated parameters.

max(array$values):mixed

Or,

max(mixed$value1[,mixed $...]):mixed

• If only one parameter is given, it should be an array of values which may be of same or different types.
• If two or more parameters are given, they should be any comparable values of same or different types.

PHP max() function returns the highest value from the array parameter or sequence of values. Standard comparison operators are applicable. If multiple values of different types evaluate as equal (e.g. 0 and ‘PHP’), the first parameter to the function will be returned.

Example 1

The following code returns the highest value from a numeric array.

<?php
   $arg=array(23, 5.55, 142, 56, 99);
   echo "array=";
   foreach ($arg as $i) echo $i . ",";
   echo "\n"; 
   echo "max = " . max($arg);
?>

It will produce the following output −

array=23,5.55,142,56,99,
max = 142

Example 2

The following code returns max() from an array of strings.

<?php
   $arg=array("Java", "Angular", "PHP", "C", "Kotlin");
   echo "array=";
   foreach ($arg as $i) echo $i . ",";
   echo "\n"; 
   echo "max = " . max($arg);
?>

It will produce the following output −

array=Java,Angular,PHP,C,Kotlin,
max = PHP

Example 3

In the following example, a series of string values is provided to the max() function. Let’s see how it behaves −

<?php
   $val1="Java";
   $val2="Angular";
   $val3="PHP";
   $val4="C";
   $val5="Kotlin";
   echo "values=" . $val1 . "," . $val2 . "," . $val3 . "," . 	$val4 . "," . $val5 . "\n";
   echo "max = " . max($val1, $val2, $val3,$val4,$val5);
?>

It will produce the following output −

values=Java,Angular,PHP,C,Kotlin
max = PHP

Example 4

In this example, the given array is a collection of mixed data types.

<?php
   $arg=array(23, "Java", 142, 1e2, 99);
   echo "array=";
   foreach ($arg as $i) echo $i . ",";
   echo "\n"; 
   echo "max = " . max($arg);
?>

It will produce the following output −

array=23,Java,142,100,99,
max = 142

PHP min() Function

The min () function returns the lowest element in an array, or the lowest amongst two or more comma separated parameters.

min(array$values):mixed

Or,

min(mixed$value1[,mixed $...]):mixed

• If only one parameter is given, it should be an array of values which may be of same or different types
• If two or more parameters are given, they should be any comparable values of same or different types

PHP min() function returns the lowest value from the array parameter or sequence of values. Standard comparison operators are applicable. If multiple values of different types evaluate as equal (e.g. 0 and ‘PHP’), the first parameter to the function will be returned

Example 1

The following code returns the smallest value from numeric array.

<?php
   $arg=array(23, 5.55, 142, 56, 99);
   echo "array=";
   foreach ($arg as $i) echo $i . ",";
   echo "\n"; 
   echo "min = " . min($arg);
?>

It will produce the following output −

array=23,5.55,142,56,99,
min = 5.55

Example 2

The following code returns min() from an array of strings.

<?php
   $arg=array("Java", "Angular", "PHP", "C", "Kotlin");
   echo "array=";
   foreach ($arg as $i) echo $i . ",";
   echo "\n"; 
   echo "min = " . min($arg);
?>

It will produce the following output −

array=Java,Angular,PHP,C,Kotlin,
min = Angular

Example 3

In this example, a series of string values is provided to the min() function.

<?php
   $val1="Java";
   $val2="Angular";
   $val3="PHP";
   $val4="C";
   $val5="Kotlin";
   echo "values=" . $val1 . "," . $val2 . "," . $val3 . "," . 	$val4 . "," . $val5 . "\n";
   echo "min = " . min($val1, $val2, $val3,$val4,$val5);
?>

It will produce the following output −

values=Java,Angular,PHP,C,Kotlin
min = Angular

Example 4

In this example, the given array is a collection of mixed data types.

<?php
   $arg=array(23, "Java", 142, 1e2, 99);
   echo "array=";
   foreach ($arg as $i) echo $i . ",";
   echo "\n"; 
   echo "min = " . min($arg);
?>

It will produce the following output −

array=23,Java,142,100,99,
min = 23

PHP pow() Function

The pow () function is used to compute the power of a certain number. It returns xy calculation, also termed as x raised to y. PHP also provides “**” as exponentiation operator.

So, pow(x,y) returns xy which is same as x**y.

pow(number$base,number$exp):number

The first parameter is the base to be raised. The second parameter is the power to which base needs to be raised.

PHP pow() function returns the base raised to the power of exp. If both arguments are non-negative integers, the result is returned as integer, otherwise it is returned as a float.

Example 1

The following example calculates 102 using pow() function −

<?php
   echo "pow(10,2) = " . pow(10,2);
   echo " using ** operator " . 10**2;
?>

It will produce the following output −

pow(10,2) = 100 using ** operator 100

Example 2

Any number raised to 0 results in 1. This is verified in the following example −

<?php
   $x=10;
   $y=0;
   echo "pow(" . $x, "," . $y . ")=". pow($x,$y);
?>

It will produce the following output −

pow(10,0)=1

Example 3

The following example shows how you can compute the square root of 100 using the pow() function −

<?php
   $x=100;
   $y=0.5;
   echo "pow(" . $x, "," . $y . ")=". pow($x,$y) . "\n";
   echo "using sqrt() function : ". sqrt(100);
?>

It will produce the following output −

pow(100,0.5)=10
using sqrt() function : 10

Example 4

This example shows how you can use the pow() function to calculate the area of a circle.

<?php
   $radius=5;
   echo "radius = " . $radius . " area = " . M_PI*pow(5,2);
?>

It will produce the following output −

radius = 5 area = 78.539816339745

PHP round() Function

The round() function proves useful in rounding any floating point number upto a desired precision level. Positive precision parameter causes the number to be rounded after the decimal point; whereas with negative precision, rounding occurs before the decimal point. Precision is “0” by default.

For example, round(10.6) returns 11, round(10.2) returns 10. The function always returns a floating point number.

This function also has another optional parameter called mode that takes one of the redefined constants described later.

round(float$value,int$precision,int$mode):float

Parameters

• Value − A float number to be rounded.
• Precision − Number of decimal digits to round to. Default is 0. Positive precision rounds given number after decimal point. Negative precision rounds the given number before decimal point.
• Mode − One of the following predefined constants.

Sr.No	Constant & Description
1	PHP_ROUND_HALF_UPRounds number away from 0 when it is half way there. Hence, 1.5 becomes 2 and -1.5 to -2
2	PHP_ROUND_HALF_DOWNRounds number towards 0 when it is half way there. Hence 1.5 becomes 1 and -1.5 to -1
3	PHP_ROUND_HALF_EVENRounds the number to nearest even value
4	PHP_ROUND_HALF_ODDRounds the number to nearest odd value

PHP round() function returns a float number that by rounding the value to a desired precision.

Example 1

The following code rounds the given number to positive precision values −

<?php
   $arg=1234.567;
   echo "round(" . $arg . ") = " . round($arg) . "\n";
   echo "round(" . $arg . ",1) = " . round($arg,1) . "\n";
   echo "round(" . $arg . ",2) = " . round($arg,2) . "";
?>

It will produce the following output −

round(1234.567) = 1235
round(1234.567,1) = 1234.6
round(1234.567,2) = 1234.57

Example 2

The following code rounds the number to negative precision values −

<?php
   $arg=1234.567;
   echo "round(" . $arg . ") = " . round($arg) . "\n";
   echo "round(" . $arg . ",-1) = " . round($arg,-1) . "\n";
   echo "round(" . $arg . ",-2) = " . round($arg,-2) . "";
?>

It will produce the following output −

round(1234.567) = 1235
round(1234.567,-1) = 1230
round(1234.567,-2) = 1200

Example 3

The following code uses UP and DOWN mode constants for rounding −

<?php
   echo "round(3.45,HALF_UP) = " . round(3.45,0, PHP_ROUND_HALF_UP) . "\n";
   echo "round(3.75 HALF_UP) = " . round(3.75, 1, PHP_ROUND_HALF_DOWN) . "";
?>

It will produce the following output −

round(3.45,HALF_UP) = 3
round(3.75 HALF_UP) = 3.7

Example 4

The following code uses ODD and EVEN modes for rounding −

<?php
   echo "round( 3.45,HALF_ODD) = " . round(3.45,0, PHP_ROUND_HALF_ODD) . "\n";
   echo "round(3.78 HALF_EVEN) = " . round(3.78, 0, PHP_ROUND_HALF_EVEN) . "";
?>

It will produce the following output −

round(3.45,HALF_ODD) = 3
round(3.78, HALF_EVEN) = 4

PHP sqrt() Function

The sqrt() function returns the square root of a positive float number. Since square root for a negative number is not defined, it returns NAN. This is one of the most commonly used functions. This function always returns a floating point number.

sqrt(float$arg):float

PHP sqrt() function returns the square root of the given arg number. For negative numbers, the function returns NAN.

Example 1

The following code calculates the square root of 100 −

<?php
   $arg = 100;
   echo "Square root of " . $arg . "=" . sqrt($arg) . "";
?>

It will produce the following output −

Square root of 100=10

Example 2

For sqrt(2), 1/sqrt(2) and sqrt(3), PHP has special predefined constants M_SQRT2, M_SQRT1_2 and M_SQRT3, respectively.

<?php
   echo "sqrt(2) = " . sqrt(2) . "\n";
   echo "M_SQRT2 = " . M_SQRT2. "\n";
   echo "sqrt(3) = " . sqrt(3) . "\n";
   echo "M_SQRT3 = " . M_SQRT3 . "\n";
   echo "1/sqrt(2)) = " . 1/sqrt(2) . "\n";
   echo "M_SQRT1_2 = " . M_SQRT1_2 . "";
?>

It will produce the following output −

sqrt(2) = 1.4142135623731
M_SQRT2 = 1.4142135623731
sqrt(3) = 1.7320508075689
M_SQRT3 = 1.7320508075689
1/sqrt(2)) = 0.70710678118655
M_SQRT1_2 = 0.70710678118655

Example 3

The mathematical constants M_SQRTPI and M_2_SQRTPI represent values of sqrt() and 2/sqrt().

<?php
   echo "sqrt(pi) = " . sqrt(M_PI) . "\n";
   echo "M_SQRTPI = " . M_SQRTPI. "\n";
   echo "2/sqrt(pi) = " . 2/sqrt(M_PI) . "\n";
   echo "M_2_SQRTPI = " . M_2_SQRTPI . "";
?>

It will produce the following output −

sqrt(pi) = 1.7724538509055
M_SQRTPI = 1.7724538509055
2/sqrt(pi) = 1.1283791670955
M_2_SQRTPI = 1.1283791670955

Example 4

sqrt(-1) is undefined, hence it returns NAN.

<?php
   echo "sqrt(-1) = " . sqrt(-1) . "";
?>

It will produce the following output −

sqrt(-1) = NAN

Predefined Mathematical Constants

In addition to the above mathematical functions, PHP also has the following list of predefined mathematical constants −

Constant	Value	Description
M_PI	3.14159265358979323846	Pi
M_E	2.7182818284590452354	Euler Number e
M_LOG2E	1.4426950408889634074	log2 e
M_LOG10E	0.43429448190325182765	log10 e
M_LN2	0.69314718055994530942	loge 2
M_LN10	M_LN10 2.30258509299404568402 loge 10	loge 10
M_PI_2	1.57079632679489661923	pi/2
M_PI_4	0.78539816339744830962	pi/4
M_1_PI	0.31830988618379067154	1/pi
M_2_PI	0.63661977236758134308	2/pi
M_SQRTPI	1.77245385090551602729	sqrt(pi)
M_2_SQRTPI	1.12837916709551257390	2/sqrt(pi)
M_SQRT2	1.41421356237309504880	sqrt(2)
M_SQRT3	1.73205080756887729352	sqrt(3)
M_SQRT1_2	0.70710678118654752440	1/sqrt(2)
M_LNPI	1.14472988584940017414	loge(pi)
M_EULER	0.57721566490153286061	Euler constant
PHP_ROUND_HALF_UP	1	Round halves up
PHP_ROUND_HALF_DOWN	2	Round halves down
PHP_ROUND_HALF_EVEN	3	Round halves to even numbers
PHP_ROUND_HALF_ODD	4	Round halves to odd numbers
NAN	NAN	Not A Number
INF	INF	Infinity